The tinnie was on a custom- made trailer and was originally used by rowing New Zealand staff to follow crews training on Lake Karipiro.
That was up until three years ago when Mr Sisley, a keen fisherman, decided it was the perfect size for him to launch for fishing and setting out nets.
"It will be hard to replace my tinnie. I could handle it myself ," Mr Sisley said. "Whatever they did, they did it very quietly because I'm a light sleeper."
Mr Sisley served in World War II and then volunteered for the Korean War as part of the 16th Field Regiment.
On returning home he went to the family sheep and beef farm in the "back blocks" of Taranaki before moving to south Waikato to farm with his wife and two sons.
But it was the lure of the Bay of Islands, the warm climate and good fishing spots that saw him sell up the farm in 1984.
"I've caught some pretty good fish out of that boat including some 20-pound snapper in a spot just off Russell," he said.
He reckons he doesn't deserve to have his boat taken and all he wants is for it to be returned so he can catch some more big ones.